Abstract: :
Purpose: Castor oil emulsion eyedrops are lipid containing eyedropswhich are thought to modify the tear film lipid layer and increasethe tear film stability. The primary objectives of the investigationwere to measure the residency time and quantify the effectsof castor oil eyedrops on the tear film lipid layer of normaland dry eyes. A secondary objective was to quantify the initialeffects on ocular symptomatology.Methods: The investigation was an open label unmasked pilotstudy carried out on 15 non contact lens wearers (5 normal and10 reporting dry eye symptoms). A single non preserved emulsioneye drop (Investigational formula, Allergan) was instilled ineach eye and the tear film appearance and composition were monitoredfor 4 hours post instillation. The tear film stability and thelipid layer thickness were evaluated with the TearscopeTM noninvasive lighting system and slit lamp biomicroscope observationsystem at 15 minutes, 1 hour and 4 hours after eyedrop instillation.The tear lipid composition and the residual presence of castoroil in the tears were monitored via tear film sampling of thetear fluid and subsequent HPLC analysis at the same time periods.Results: The combined results for both normal and dry eye subjectsshow that: i. Castor oil presence was detected up to four hourspost a single eyedrop instillation; ii. The volume of lipidpresent in the tear film increased post instillation; iii. Thesymptoms of dryness (p=0.006 to 0.024), itchiness (p=0.001 to0.014), burning (p<0.001 to 0.039) and scratchiness (p=0.025to 0.044) were significantly lower up to 4 hours post instillation;iv. A significantly lower incidence of thin tear film lipidpatterns was recorded up to 1 hour post instillation comparedto baseline particularly for the symptomatic subjects (p=0.031).Conclusions: This pilot investigation showed that castor oilemulsion eyedrops interact synergistically with the tear filmlipid layer for up to 4 hours post instillation and producean associated decrease in ocular symptoms. In general, a greatereffect was observed for symptomatic patients.